الفهرس 
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Abstract
Data of this study on milk and reproductive traits of Austrian Fleckvieh cows were collected by the Official test Federation of Austrian Cattle Breeders (ZAR) in lower Austria. Data analysis was carried out in the Department of Animal Production, Faculty of Agriculture, Zagazig University, Egypt. Data consisted of monthly test-day records of milk and reproductive traits on Flecvieh cow calved on seven consecutive years during the period from 1994 to 2000. The study comprised 19755 test day (TD) records for the first parity of paternal half-sisters of 19755 Flecvieh cows, daughters of 57 sires and 19755 dams. All daughters were obtained from AI bulls. Heifers were inseminated when they reached about 320 kg body weight. Preliminary analyses of data carried out using Statistical Analysis System (SAS) version 9.1 for Windows, were used to study the fixed effects of {month and year of calving on 305-day milk yield (MY305, kg), 305-day fat yield (FY305, kg), 305-day protein yield (PY305, kg), lactation somatic cell score (LSCS), age at first calving (AFC, months) and days open (DO, days)}. In addition, the data were analyzed by using animal models (AM) to estimate genetic parameters. Least squares analysis of variance showed significant effects of month and year of calving on most milk traits studied. The linear and quadratic regression coefficients of AFC and DO on MY305, FY305, PY305 and LSCS, were significant. Estimates of heritability were 0.40±0.02, 0.55±0.40, 0.48±0.08, 0.08±0.02, 0.18±0.01 and 0.05±0.01 for the above-mentioned traits, respectively. Genetic correlations among MY305, FY305, PY305, AFC and DO were positive and ranged from 0.52±0.14 (between MY305 and PY305) to 1.00±0.02 (between FY305 and PY305). The correlations with LSCS were negative and ranged from -0.08±0.02 (between DO and LSCS) to -0.25±014 (between AFC and LSCS).